As a conventional conveyor belt apparatus capable of detecting vertical cracks of a conveyor belt, for example, a constitution as indicated in Patent Literature 1 below is known. Such a conveyor belt apparatus is equipped with a conveyor belt in which a loop coil is embedded in a main body rubber extending in a belt longitudinal direction, a magnetic generator for generating a magnetic field that produces an induced current in a loop coil, and a detector for detecting the induced current produced in the loop coil. The loop coil has an annular shape in plan view taken in a belt thickness direction. In the conveyor belt apparatus, if vertical cracks are formed at the conveyor belt and the loop coil is disconnected, the induced current occurring at the loop coil when the magnetic field is generated from the magnetic generator is changed, and thus the vertical cracks are detected by the detector.
In general, a part of the conveyor belt which runs in the belt longitudinal direction undergoes bending deformation in a belt width direction. In a state in which such a part is subjected to the bending deformation, for instance, in a trough shape or in a pipe shape, conveyance items are conveyed in the belt longitudinal direction.